Stuart Murray sits down with Winnipeg writer, filmmaker, and environmental advocate Erna Buffie. After more than two decades producing science documentaries for CBC's The Nature of Things, Erna has turned her attention closer to home — documenting why Winnipeg's urban forest is in crisis, and what it will take to save it. Her book Out on a Limb makes the case that trees aren't a civic amenity. They're essential infrastructure.We're talking:Why Winnipeg — despite its iconic canopy of elms — scores among the lowest of major Canadian cities for greenness, and what's driving that declineThe health benefits of urban trees and the argument for treating trees as infrastructure: for every $1 invested in a tree, the city sees $6 in benefitsWhy "we'll just plant more" isn't the answer — and why it takes a minimum of 10 years for a sapling to deliver even a fraction of what a mature tree providesThe case for a private tree bylaw — why more than 700 cities have passed them, and why Winnipeg has been reluctant to followAs Erna puts it, trees aren't just a pretty way to beautify a city. They cool the air, capture pollutants, absorb rainwater, support biodiversity, and help us build the kind of climate resilience we're going to need. The science is clear. What's missing is political will.“Out on a Limb” is out now. There will be a book launch event on Wednesday May 20, 7:00 pm, at McNally Robinson in Grant ParkCheck out Out on a LimbLearn more about Trees Please Winnipeg